Full text of "TM 11-351 Telegraph Sets TG-5, TG-5-A, And TG-5-B"

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OF THE

UNIVERSITY

CALIFOR^

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TELEGRAPH SETS

TG-5, TG-5-A, AND TG-5-B

WAri IM I IMUl ■ The material forming the subject matter of this manual is the property
of the United States Government and it is printed and distributed solely for the use of the
military, naval, and civilian personnel of the War and Navy Departments, and may not
be published or reproduced in whole or in part in any manner or form (except by lawful
copyright holders who may reproduce their copyrighted material in its original form) except
upon specific approval by authorized military public relations agencies,

artArtY %

NOV 5 1948

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WAR DEPARTMENT

JUNE 1945

WAR DEPARTMENT TECHNICAL MANUAL

TM 11-351

This manual supersedes TM 11-351,22 September 1941, including C 1, 23 January 1942,
C2, 22 July 1943; TB 11-351-1, 23 June 1944, and TB 11-351-2, 4 November 1944.

TELEGRAPH SETS

TG-5. TG-5-A, AND TG-5-B

WAR DEPARTM ENT

JUNE 1945

WARNING: The material forming the subject matter of this manual is the
property of the United States Government and it is printed and distributed solely
for the use of the military, naval, and civilian personnel of the War and Navy Depart-
ments, and may not be published or reproduced in whole or in part in any manner or
form (except by lawful copyright holders who may reproduce their copyrighted mate-
rial in its original form) except upon specific approval by authorized military public
relations agencies.

United States Government Printing Office
W ashing ton : 1945

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WAR DEPARTMENT
Washington 25, D. C, IS June 1945

TM 11-351, Telegraph Sets TG-5, TG-5-A, and TG-5-B, is published
for the information and guidance of all concerned.

[AG300.7(21Dec44>]

By Order of the Secretary of War:

Official: G. C. MARSHALL

J. A. ULIO Chie f °f Sta ff

Major General

The Adjutant General

Distribution :

AAF (5) ; AGF (5) ; ASF (2) ; T of Opn (5) ; Dept (5) ; Base
Comd (5) ; Island Comd (5) ; Gulf Comd (5) ; AAF Comds (2) ;
Arm & Sv Bd ( 1 ) ; Def Comd (2) ; S Div ASF ( 1 ) ; Tech Sv (2) ;
SvC (5) ; PC&S (2) ; PE (2) ; Dep 11 (2) ; Gen Oversea SOS
Dep (2) ; Pro Dist 11 (2) ; Gen & Sp Sv Sch (5) ; USMA (10) ;
ROTC (2); Lab 11 (2); Sig AS (2); WDGS Lib (5); Rep
Shops 11 (2) ; A (5) ; CHQ (5) ; D (2) ; AF (2) ; Three (3)
copies to each of the following: T/O and E 1-27; 1-37; 1-67
1-117; 1-127; 1-137; 1-167; 1-267; 1-287; 1-312; 1-397; 1-452
1-487; 1-547; 1-637; 1-652; 1-757; 1-759; 1-768; 1-1027; 5-512S
6-10-1 ; 6-12; 6-20-1 ; 6-26; 6-36; 6-46; 6-50-1 ; 6-56; 6-76; 6-86
6-110-1 ; 6-150-1 ; 6-160-1 ; 6-166; 6-186; 6-200-1 ; 6-212; 6-216
6-226; 7-12; 7-16; 7-32; 7-36; 7-52; 7-56; 7-72; 7-76; 7-86
7-96; 7-132; 7-136; 7-416; 11-7; 11-18; 11-47; 11-57; 11-77
11-88; 11-97; 11-107; 11-127; 11-147; 11-217; 11-237; 11-247
11-257; 11-267; 11-267S; 11-287; 11-317; 11-337; 11-338; 11-400,
Sig AW Orgn— (J) Wire; 11-450-1; 11-460-1; 11-500, Sig Sv
Orgn— (IS), (IV); 11-537; 11-557; 11-577; 11-587; 11-592;
11-597; 19-46; 44-7; 44-276.

Refer to FM 21-6 for explanation of distribution formula.

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DESTRUCTION NOTICE — fV) „ - 3 3- )

±1M

WHY — To prevent the enemy from using or salvaging this equipment for
his benefit.

WHEN — When ordered by your commander.

HOW — 1- Smash — Use sledges, axes, handaxes, pickaxes, hammers, crow-
bars, heavy tools.

2. Cut — Use axes, handaxes, machetes.

3. Burn — Use gasoline, kerosene, oil, flame throwers, incendiary

grenades.

4. Explosives — Use firearms, grenades, TNT.

5. Disposal — Bury in slit trenches, fox holes, other holes. Throw

in streams. Scatter.

USE ANYTHING IMMEDIATELY AVAILABLE FOR DESTRUCTION

OF THIS EQUIPMENT

WHAT — 1- Smash — Interrupter, relay, key, terminal blocks, and case.

2. Cut — Chassis wiring, cords, and case.

3. Burn — All remaining equipment, smashed parts, Technical

Manuals, circuit labels, and traffic diagrams.

4. Bury or scatter — All of the above pieces after destroying their

S usefulness.

DESTROY EVERYTHING

M609733

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IV
CONTENTS

PART ONE. INTRODUCTION. Paragraph Page

Section I. Description of Telegraph Sets TG-5, TG-5-A, and TG-5-B.

General 1 1

Description 2 1

Packing for export 3 &

Differences in models of Telegraph Set TG-5-(*) 4 1

II. Application.

General 5 8

Range 6 10

77/. Installation and assembly.

Uncrating, unpacking, and checking 7 11

Locating 8 11

Installation of batteries 9 11

Connection of incoming lines 10 13

Connection of Telegraph Set TG-5-(*) for use as a tone

keyer 11 13

Repacking for transportation and storage 12 14

IV. Initial adjustments.

Preliminary tests 13 15

Preliminary adjustments 14 15

PART TWO. OPERATING INSTRUCTIONS.

Section V. Procedure for operation.

Adjustment of Relay BK-7-(*) 15 U

Additional line battery 16 V

Operation 17 18

VI. Equipment performance check sheet.

Purpose and use of equipment performance check sheet. . 18 18

Equipment performance check sheet 19 1?

PART THREE. PREVENTIVE MAINTENANCE.

Section VII. Preventive maintenance techniques.

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Meaning of preventive maintenance 20 21

Description of preventive maintenance techniques 21 21

Common materials needed 22 21

Box, exterior 23 21

Rear battery compartment 24 21

Line battery compartment 25 21

Terminal block 26 2\

Receiver R-3 27 2\

Cord CC-33S 28 2\

Plug PL-55 29 21

Case CS-49-(*) 30 2\

Interrupters BZ-5-(*) and BZ-7-(*) 31 2\

Relays BK-7-A and BK-7-B 32 2:

Bell 33 2:

KeyMl-(*) 34

Paragraph Page

VIII. Preventive maintenance check list.

Preventive maintenance check list 35 26

IX. Lubrication (not required).

X. Moistureproofing and fungiproofing.

General 36 26

Treatment 37 27

Telegraph Set TG-5-(*) 38 27

Moistureproofing and fungiproofing after repairs 39 29

PART FOUR. AUXILIARY EQUIPMENT.

(Not used.)

PART FIVE. REPAIR INSTRUCTIONS.

Section XI. Theory of Telegraph Set TG-5-(*).

Circuit elements 40 31

Theory of operation 41 33

XII. Test equipment.

General 42 36

Voltohmmeter 1-166 43 37

Test Set TS-26/TSM 44 39

XIII. Trouble shooting.

General 45 39

Line and bell circuit 46 40

Transmitting and receiving circuit 47 41

Circuit measurements 48 42

Trouble-shooting chart 49 43

XIV, Removal and replacement of parts.

General 50 44

Terminal block 51 44

Jack 52 44

Interrupter 53 45

Bell 54 45

Capacitor 55 46

Relay 56 47

Key 57 47

Front cover catch 58 47

XV. Special procedures.

Adjustment of Relays BK-7 and BK-7-A 59 47

Adjustment of Relay BK-7-B 60 48

Burnishing and adjusting contacts of Jack J K-35 61 51

Painting and refinishing 62 52

Unsatisfactory equipment report 63 53

APPENDIX I. MAINTENANCE PARTS 55

II. REFERENCES 56

*.
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This manual supersedes TM 11-351, 22 September 1941, including CI, 23 January 1942,
C2, 22 July 1943; TB 11-351-1, 23 June 1944, and TB 11-351-2, 4 November 1944.

PART ONE
INTRODUCTION

Section I. DESCRIPTION OF TELEGRAPH SETS TG-5,
TG-5-A, AND TG-5-B

1. General

a. Characteristics. Telegraph Set TG-5-(*) is a portable, open-
circuit, field set designed for telegraph communication over short lines.
The set may be used on ground return circuits obtained by simplexing a
telephone circuit, or on other ground return or metallic circuits. The
range of the equipment will vary with the type of line wire used, the condi-
tion of the wire, whether the wire is wet or dry, and whether the wire is on
the ground or in the air. The telegraph set will operate satisfactorily over
field wire circuits of any length likely to be encountered within divisions or
subordinate units, provided the lines are well constructed.

b. Nomenclature. Telegraph Sets TG-5, TG-5-A, and TG-5-B are
referred to in this manual as Telegraph Set TG-5-(*). Such nomenclature
refers to any one or all of the above three models. Similarly, Relay
BK-7-(*) refers to Relays BK-7, BK-7-A, and BK-7-B; Case
CS-49-(*) refers to Cases CS-49 and CS-49-A; Key J-41-(*) refers
to Keys J-41 and J-41-A; Interrupter BZ-7-(*) refers to Interrupters
BZ-7-A, BZ-7-C, BZ-7-J, and BZ-7-N; and Interrupter BZ-5-(*)
refers to Interrupters BZ-5 and BZ-5-G.

2. Description

a. Case CS-49-(*) (fig. 2). The case is made of heavy olive-drab
canvas with leather reinforced bottom and corners. The cover is hinged at
the back, overlaps the sides and front, and fastens in front with a snap

fastener. Sewed to the sides of the case is an adjustable carrying strap

approximately 2 inches wide and 85 inches long.

b. Box (figs. 3, 4, and 5). The box which contains the circuit elements
of Telegraph Set TG-5-(*) is constructed of sheet metal and is approxi-
mately $ l / 2 inches high, 10 inches long, and 5 l / 2 inches deep. The box is
provided with a hinged front and cover. When closed, the cover projects
over the front edge of the box and holds the front in place. In the closed
position a spring catch on the front engages with a hasp mounted on the
cover and serves to hold the cover closed. When open, the front folds down

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Figure 2. Telegraph Set TG-5 and Case CS-49.

to form a shelf upon which Key J— 41— (*) is mounted. A wiring diagram
of Telegraph Set TG-5-(*) is mounted on the inside of the cover. On
the inside of the box, near the back, a compartment is provided for
installing one Battery BA-2. To the right of this compartment a space is
provided for storing the headset when not in use. In the rear of the box,
a hinged door, held in place by a locking screw, provides access to the
battery compartment which is designed to hold two Batteries BA— 30.
(See fig. 6.)

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BATTERY
COMPARTMENT
(BATTERY BA"2)

WIRING DIAGRAM

CONTACT BURNISHER

RECEIVER COMPARTMENT
TERMINAL BLOCK
INTERRUPTER BZ*7"A

RECEIVER R-3

Figure 4. Telegraph Set TG-5-A, cover open.

Figure 5. Telegraph Set TG-5-B, cover open.

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BATTERY
COMPARTMENT DOOR

Figure 6. Telegraph Set TG-5-B, rear view.

c. Terminal Block. (1) The terminal block on Telegraph Set TG-5
is fastened to the front of the battery compartment with two screws. It
consists of a piece of bakelite 4 inches long, 7/16 inches wide, and 5/16
inches thick. Five Binding Posts TM-150 are mounted on the terminal
block and are labeled from left to right — 3V, +, 22V— , LI, and L2. (See
fig. 3.)

(2) The terminal block on Telegraph Sets TG-5-A and TG-5-B con-
sists of a molded phenolic block 2J4 inches long, 1 Y% inches wide, and Y&
inches thick. Two Binding Posts TM-175 are mounted on the upper right-
hand portion of the block and are labeled LI and L2. Three Binding Posts
TM-150 are mounted on the lower portion of the block and are labeled,
from right to left —3, +, and —22. (See figs. 4 and 5.)

d. Relay BK-7-(*). (1) Relay BK-7. Relay BK-7 is used in Tele-
graph Set TG-5 only. The relay is contained in a black bakelite housing
and is mounted on the left side of the box just below the battery compart-
ment. The front of the relay contains two levers for the adjustment of the
relay spring tension and the armature air gap. The lever on the left is
labeled SPRING and the one on the right GAP. Both levers move over a
scale graduated from to 30. ( See fig. 3.)

(2) Relay BK-7 -A. Relay BK-7-A is part of Telegraph Set TG-5-A
only. The relay is mounted on a bracket directly in front of the battery
compartment and is similar in appearance to RELAY BK-7. Two levers
mounted on the front of the relay are labeled SPRING and GAP and move
over a scale graduated from to 20. An opening, in the top of the relay
case, provides access to the relay contacts for cleaning purposes, (See
fig. 4.)

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(3) Relay BK-7-B. Relay BK-7-B is part of Teiegraph Set TG-5-B
only. The relay is mounted on a bracket in front of the battery compart-
ment and is similar in appearance to Relays BK-7 and BK-7-A. One
lever, mounted on the front of the relay case, is labeled ADJUST and
moves over a scale graduated from to 40. The armature remains in a
fixed position in this relay and the lever adjusts only the spring tension on
the movable contact. An opening, in the top of the relay case, provides
access to the relay contacts. This opening is provided with a small clip-on
metal cover. (See fig. 5.)

e. Bell (figs. 3, 4, and 5). The bell used in Telegraph Set TG-5-(*) is
a d-c vibrator type and is fitted with a 1 %-inch gong- A small screw on the
side of the bell frame provides a means of adjusting the distance between
the fixed contact and the movable contact mounted on the clapper arm.
In Telegraph Set TG-5 the bell is mounted between the receiver compart-
ment and the right side of the case. In Telegraph Sets TG-5-A and
TG-5-B the bell is mounted directly under the relay.

/. Interrupter BZ-S (fig. 3). Interrupter BZ-5 is part of Telegraph
Set TG-5 only. The interrupter (howler) serves as a local tone source for
the operator and consists of a double carbon button mounted against the
diaphragm of a telephone receiver. When operating, the interrupter pro-
duces a steady tone of approximately 1,000 cycles per second. The inter-
rupter is mounted in front of the receiver compartment by means of two
screws through the bottom of the box.

g. Interrupter BZ-5-G. Interrupter BZ-5-G consists of two single
carbon buttons mounted side by side against a common transmitter dia-
phragm and this combination mounted directly over two receiver dia-
phragms. When operating, the interrupter produces a continuous tone of
approximately 1,000 cycles.

. h. Interrupters BZ-7-A, BZ-7-C, and BZ-7-J (fig. 4). Interrupter
BZ-7-A, BZ-7-C, or BZ-7-J is part of Telegraph Set TG-5-A only and
is mounted ,by means of two screws through the bottom of the box, imme-
diately in front of the receiver compartment. It consists of a single carbon
button mounted against a receiver diaphragm. When operating, the inter-
rupter produces a continuous tone of approximately 1,000 cycles per second.

Note. Interrupter BZ-5 and Interrupters BZ-7-A, BZ-7-C, and BZ-7-J will
operate only in the vertical position.

i. Interrupter BZ-7-N (fig. 5). Interrupter BZ-7-N is part of Tele-
graph Set TG-S-B and is mounted in front of and below the receiver com-
partment. This interrupter is electrically similar to Interrupter BZ-7-A
but much smaller in size, and is designed to operate when held in any
position.

/. Jack JK-35 (figs. 3, 4, and 5). Jack JK-35 is a tip-sleeve type jack
with an extra set of contacts, equivalent to a single-pole, double-throw

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switch, operated by the tip spring. The jack is mounted in the lower right-
hand corner of the box.

k. Key J-41-(*) (figs. 3, 4, and 5). Key J— 41— (*) is an open-circuit
telegraph type key mounted on a molded phenolic base which, in turn, is
mounted on the folding front portion of the box. The key contains two
sets of contacts, one set toward the front of the key lever and the other at
the back. In the normal position, the front contacts are open and the back
contacts are closed. Three binding posts, two on the right and one on the
left, are provided for connecting the key into the circuit. A knurled screw
and locknut at the rear of the key lever provides a means of adjusting
the opening between the front contacts. Another knurled screw and lock-
nut toward the front of the lever is used to adjust the tension of the spring
which keeps the front contacts open. The key lever is mounted on the frame
by means of two knurled screws threaded through the sides of the frame.

/. Headset HS-20 (figs. 3, 4, and 5). Headset HS-20 consists of Re-
ceiver R-3, Cord CC-33S, and Plug PL-S5.

( 1 ) The receiver is the magnetic type having a d-c resistance of approxi-
mately 80 ohms. The receiver is contained in a watch type case having
an adjustable web headband fastened to brackets on the sides of the case.

(2) The cord consists of approximately 4 feet of two-conductor, twisted,
rubber- and braid-covered cord terminating in Plug PL-55.

3. Packing for Export

Telegraph Set TG-5-(*) is packed for export in the following manner:

a. One dustproof bag containing 4 ounces of silica gel is placed in the
large battery compartment, and two dustproof bags each containing 1
ounce of silica gel are placed in the rear battery compartment.

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b. The telegraph set is placed in its carrying case and the cover snapped
shut.

c. The telegraph set is then placed in a fiberboard container with the
front of the set up. The strap is neatly folded on the front of the case. One
pound of silica gel in a dustproof bag is placed beside the folded strap.

d. The fiberboard container is then closed, sealed, and wrapped in a

moistureproof and vaporproof paper. (See fig. 7.)
i

e. This container and wrapping is then placed in a fiberboard box and

sealed with gummed tape.

/. If more than one telegraph set is to be shipped at one time, six sets
are placed in a nailed wooden crate approximately 23 inches wide, 23 inches
deep, and 23 inches long. ( See fig. 8.)

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OUTER /

CONTAINER

INNER.
CONTAINER

siuca aa\

WATERPROOF
BARRIER

CASE C$M9-(»r

(CONTAJNINQ TCUOMAPli SCT T» -#-(»))

tL»27T#-t

Figure 7. Telegraph Set TG-5-B, packed for export

4. Differences in Models of Telegraph Set TG-5-{*)

The differences in models of components of Telegraph Set TG-5-(*)
are described in paragraph 2. Operation is the same for all models with
the exception of the adjustment of Relay BK-7-(*). This adjustment is
covered in section V. Telegraph Set TG-5 weighs approximately 6 pounds
and Telegraph Sets TG-5-A and TG-5-B weigh approximately 7 pounds,
including batteries.

Figure 8. Packing case.

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Section II. APPLICATION

5. General

Telegraph Set TG-5-(*) may be connected directly to each other by
metallic or ground return circuits, or may be used in conjunction with
existing wire systems to provide additional communication channels. In
either case operation of the telegraph set is the same. The telegraph set
can also be used as a tone keyer for voice-modulated radio sets, permitting
transmission of International Morse Code over radio sets originally de-
signed for voice operation only.

a. When used on metallic or ground return lines, two telegraph sets may
be connected in series as terminal stations and one or more telegraph sets
connected in series with them as intermediate stations. No more than
three or four telegraph sets however, can be so connected and still operate
properly.

TELEGRAPH SET TG-5-(*0
(TERMINAL STATION)

TELEGRAPH SET TG-5-(*)
(TERMINAL STATION)

CIO-

L 20-

LINE WIRES

•OLI

OL2

TLS277**

Figure 9. Block diagram, Telegraph Set TG-5-(*), metallic circuit.

TELEGRAPH SET TG-5-0O
(TERMINAL STATION)

TELEGRAPH SET TG-S-<*)
(TERMINAL STATION)

LIO-
L20-

LINE WIRE

OLI
>L2

TL51TTT-*

Figure 10. Block diagram, Telegraph Set TG-5-(*), ground return circuit.

TELEGRAPH TG-5-00

(TERMINAL STATION)

LIO-

L20-

TELEGRAPH SET TG-5-(rt
(INTERMEDIATE STATION)

TELEGRAPH SET TG-5-(*)
.(TERMINAL STATION)

-OLI

LI L2

j -OL2

TL M77»-»

Figure 11. Block' diagram, Telegraph Set TG-5-(*), ground return circuit with

intermediate station.

b. When used in conjunction with existing wire systems, two telegraph
sets may be connected in series as terminal stations or one or more con-
nected in series with them as intermediate stations on a simplex, phantom,

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or simplex-phantom circuit by use of repeating coils contained in the equip-
ment with which they are operated.

TO
TELEPHONE

OR
SWITCHBOARD

REPEATING
COIL

TELEPHONE LINE

TELEGRAPH SET
TG-5-<*>

(TERMINAL
STATION)

•* TO
TELEPHONE

OR
SWITCHBOARD

TELEGRAPH SET
TG-5-00

(TERMINAL STATION)
TL&1770-4

TO
SWlTCMBOAftD

TCLCi

i r

Figure 12. Block diagram, Telephone Set TG-5-(*), simplex circuit

TING REPEATING

L COIL

COB

REPEATING
COIL

Ll<
L2<

LINE
WIRES

TG ^

TO SWITCHBOARD
OR
TEST STATION

TELEGRAPH SET TG-5-(*>
(TERMINAL STATION)

LI L2

LINE
WIRES

TO
SWITCHBOARD

OR
TELEPHONE

TELEGRAPH SET TG-5-00
(TERMINAL fTATION)

TELEGRAPH SET TG-5-H»l
(INTERMEDIATE STATION")

>LI
>l 2

•TUMTW-*

Figure 13. Block diagram, Telegraph Set TG-5-(*), simplex circuit with

intermediate station.

TO
TELEPHONE
OR
SWITCHBOARD

TELEGRAPH SET
TG-5-W
(TERMINAL STATION)

TELEPHONE

SWITCHBOARD

LINE
WIRES

TO
TELEPHONE
OR
** SWITCHBOARD

TELEGRAPH SET

TG-5-C*)
(TERMINAL STATION)

TELEPHONE
OR
•» SWITCHBOARD

TL 52761 -S

Figure 14. Block diagram, Telegraph Set TG-5-(*), phantom circuit.

c. Telegraph Set TG-5-(*) will operate satisfactorily as a tone keyer
with any Signal Corps radio using a standard carbon button microphone,
such as Radio Sets SCR-300, SCR-508, SCR-S10, SCR-608, SCR-610,
and SCR-619. An adapter cord is necessary to permit the use of the tele-
graph set as a tone keyer. This cord consists of a two-conductor cord ter-
minating in Plug PL-55 on one end and Plug PL-68 on the other. The cord
is so wired that the tip and sleeve of Plug PL-68 are connected together
and through the cord to the sleeve of Plug PL-55. The ring of Plug PL-68

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LINE WIRES

TELEGRAPH SET TG-S-(ft)
(TERMINAL STATION)

UO-r
L2

TELEGRAPH SET "±r

TG-5-00
(TERMINAL STATION)

LINE WIRES

•S.

TL*27»2-S

Figure 15. Block diagram, Telegraph Set TG-5-(*), simplex-phantom circuit.

is connected through the cord to the tip of Plug PL-55 in series with a
400-ohm, J^-watt resistor. The resistor is connected in the circuit to pre-
vent r-f feedback which results in steady tone modulation in some cases.

TELEGRAPH
SET
TG-3-00

•

VOICE -MODULATED RADIO
TRANSMITTER

"^JACK JK-35

^CARBON BUTTON
MICROPHONE JACK

AOAP

TER CORD

Tt 42T»J-

Figure 16. Block diagram, Telegraph Set TG-5-(*), used as a tone keyer on voice-
modulated radio set.

6* Range

The range of Telegraph Set TG-5-(*) is dependent on the type, construc-
tion, and condition of the wire lines used, weather conditions, adjustment
of the relay, condition of the battery in the set, and the type of telegraph
sets working together. When the conditions given above are at their best,
the following ranges can be expected on a simplex circuit :

a. Two Telegraph Sets TG-5-A working together will operate satis-
factorily, at a speed of 20 words per minute (wpm), over 50 miles of
wet Wire W-110-B. On dry Wire W-110-B the sets will operate
satisfactorily when the total resistance of the line does not exceed
23,000 ohms.

b. Two Telegraph Sets TG-5-B working together will operate satis-
factorily at a speed of 15 wpm, over 50 miles of wet Wire W-110-B.
On dry Wire W-110-B the sets will operate satisfactorily when the total
resistance of the line does not exceed 72,000 ohms.

c. Telegraph Set TG-5-A working with Telegraph Set TG-5-B will
operate satisfactorily, at a speed of 20 wpm, over 30 miles of wet Wire
W-110-B. Over dry Wire W-110-B the sets will operate satisfactorily
when the resistance of the line does not exceed 26,000 ohms.

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Section III. INSTALLATION AND ASSEMBLY

7. Uncrating, Unpacking, and Checking

Telegraph Sets TG-5-(*) are packed in a nailed wooden box as shown
in figure 8. Each wooden box contains six telegraph sets which are
individually packed in fiberboard packing boxes. (See fig. 7.) To unpack
the telegraph sets follow the procedure 'outlined below.

a. Place the wooden box in a convenient place for opening.

b. Cut and remove the steel straps.

c. Remove the nails from the top and sides of tne box with a nail
puller, and remove the top. Do not pry off the top of the box as this
may cause damage to the equipment.

d. Remove the individually packaged telegraph sets from the wooden
box.

e. Open the top of each fiberboard container and remove the inner
fiberboard container and moistureproof wrapping.

/. Remove the moistureproof wrapping from the inner fiberboard con-
tainer.

g. Open the top of the inner container.

h. Withdraw the telegraph set from the inner container.

i. Open the case and remove the telegraph set.

j. Open the telegraph set and remove the silica gel from the battery
compartment.

k. Open the rear battery compartment and remove the silica gel.

/. Carefully inspect the equipment for possible damage during ship-
ment.

8. Locating

Locate Telegraph Set TG-5-(*) where it will not be subject to adverse
weather conditions. Place the telegraph set in an upright position in a
manner providing convenient access to the key. A wooden frame is
desirable for holding the telegraph set in position if it is to be installed
semipermanently on a table or other flat surface.

9. Installation of Batteries

a. Installing Battery BA-2. (1) Open the cover of the set.

(2) Place one Battery BA-2 in the battery compartment.

(3) Connect the positive lead (red wire) to + terminal on the ter-
minal block.

(4) Connect the negative lead (black wire) to the —22 terminal on

f™' f\j~ifiL:> Original from

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the terminal block on Telegraph Set TG-5-A or TG-5-B, or to the
terminal marked 22V— on Telegraph Set TG-5.

b. Installing Batteries BA-30 (fig. 17), (1) Open the battery
compartment in the rear of the telegraph set.

(2) Place one Battery BA-30 in the battery compartment so that the
bottom (negative contact) is against the spring mounted on the right
side of the compartment.

(3) Place a second Battery BA-30 in the compartment so that the
bottom presses against the positive contact of the first battery installed
and the positive contact presses against the flat metal spring on the left
side of the compartment.

POSITIVE
CONTACT

BATTERIES ■ ■>. NEGATIVE
BA-30 ♦ ' CONTACT

TL52784"Sj

Figure 17. Batteries BA-30 installed in Telegraph Set TG-5-B.

c. External Battery. (1) If Batteries BA-30 are not available,
any 3-volt d-c source of power may be used by connecting the positive
lead to the terminals on the terminal block marked -|- and the negative
lead to the terminal marked —3. Remove any batteries installed in the
rear battery compartment before connecting an external battery and be
sure that the voltage of the external source does not exceed 3 volts.

(2) If Battery BA-2 is not available, any 22^-volt d-c source of
power may be used by connecting the positive lead to the terminal marked
+ on the terminal block and the negative lead to the terminal marked
—22 on the terminal block of Telegraph Set TG-5-A or TG-5-B or to
the terminal marked 22 V— on Telegraph Set TG-5. Remove any Battery
BA-2 from the telegraph set before connecting an external source of
power and be sure the voltage of the external source does not exceed
22^ volts.

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10. Connection of Incoming Lines

(fig. 18)

a. Remove Telegraph Set TG-5-(*) from Case CS-49-(*).

b. Open the cover.

c. Starting approximately 4 inches from the ends of the wires to which
the telegraph set is to be connected, strip off about 2 inches of insulation.
Scrape and clean the bared metal of the wires.

d. If the telegraph set is being connected to a metallic circuit, connect
one wire of the line to the terminal marked LI on the terminal block
of the telegraph set. Connect the other line wire to the terminal marked
L2. (See fig. 18.)

e. If the telegraph set is being connected to a ground return circuit,
connect the line wire to either line terminal LI or L2. Connect the
remaining line terminal to a good ground. (See TM 11-755.)

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11. Connection of Telegraph Set TG— 5-(*) for Use as a
Tone Keyer

a. Connect a shorting wire across line terminals LI and L2 of Tele-
graph Set TG-5-(*).

b. Insert Plug PL-55 of the adapter cord into the headset jack on the
telegraph set.

c. Insert Plug PL-68 into the microphone jack of the transmitter.

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UNIVERSITY OF CALIFORNIA

400 OHM
1/2 WATT

CARBON TYPE
RESISTOR.

INSULATING
SLEEVE OVER
SOLDERED
JOINT.

PL-ee

SERVE WITH

COTTON THREAD

SIDE VIEW
SHOWING
CONNECTIONS

TL52570

Figure 19. Wiring of Plug PL-55 and Plug PL-68 for use as adapter cord zvith

Telegraph Set TG-5-(*).

Figure 20. Telegraph Set TG-5-B packed for transportation or storage.

12. Repacking for Transportation and Storage

(% 20)

a. Remove the line wires from the terminal block.

b. Close and fasten the front and cover of the telegraph set.

c. Place the telegraph set in Case CS-49-(*). Fasten the cover.

Mote. If Telegraph Set TG-5-(*) is to be transported or stored for a period longer
than 2 days, remove the batteries from the set.

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Original from ,
UNIVERSITY OF CALIFORNIA

15
Section IV- INITIAL ADJUSTMENTS

1 3. Preliminary Tests

a. Calling Circuit. Install the batteries in the set. Short circuit the
line terminals LI and L2 while alternately operating the key. The bell
should be heard when the key is depressed and not when the key is
released.

b. Transmitting and Receiving Circuit. Insert the headset plug
in the jack. The interrupter should operate and produce a faint tone.
Short the line terminals and operate the key while holding the receiver
to the ear A loud tone should be heard in the receiver when the key is
depressed but not when released.

14. Preliminary Adjustments

a. Key J-41-(*). (1) Loosen the locknuts on the four adjusting
screws.

(2) Operate the key slowly and adjust the screws on either side of
the frame until the key lever moves freely without sidewise motion.
Tighten the locknuts on these two screws.

(3) Turn the adjusting screw on the rear of the key lever until the
back contact closes when the key is unoperated and opens when it is
operated and the desired clearance is obtained between the front contacts.
Tighten the locknut.

(4) Adjust the screw on the front of the key lever until the desired
spring tension is obtained. Tighten the locknut.

b. Adjustment of Bell. Short terminals LI and L2 with a screw
driver or short piece of wire and depress the key. If the bell does not
ring proceed as follows:

(1) Insert a screw driver in the slot of the adjusting screw which
protrudes through the top of the bell frame.

(2) Turn the screw clockwise as far as it will go.

(3) Hold down the key lever.

(4) Turn the screw counterclockwise until the bell begins to ring.

c. Relay BK-7-(*). Adjustment of Relay BK-7-(*) is covered in
section V.

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Digitized by ^UU^IL UNIVERSITY OF CALIFORNIA

PART TWO
OPERATING INSTRUCTIONS

Note. For instructions to prevent use of equipment by the enemy, see the destruction

notice in the front of this manual.

Section V. PROCEDURE FOR OPERATION

15. Adjustment of Relay BK-7-{*)

a. General. The resistance of the relay in Telegraph Set TG-5-(*)
is a fixed value and it is necessary, therefore, to adjust the armature so
that it will make and break its contacts properly with various values of
current flowing through the relay winding. The resistance of the external
circuit connected to terminals LI and L2 determines the value of this
current. Consequently the relay must always be adjusted for the circuit
over which the set is to operate and may need to be adjusted frequently
as the resistance of that circuit changes or as stations are added to or
removed from that circuit. With normal line battery installed in the tele-
graph set, there is a limit to the possible adjustment and if that limit is
reached without obtaining satisfactory operation, it may be necessary
to increase the voltage on the line as described in paragraph 16.

b. Relays BK-7 and BK-7-A. When the pointers on Relays BK-7
and BK-7-A are set at 0, the armature spring tension is least and the
air gap smallest. At this setting, a current of approximately 1.0 to 1.5
milliamperes is required to operate the relay. If, however, a stronger
current flows through the relay winding, the spring tension will not be
strong enough to break the contacts quickly after the current ceases to
flow and clear signals will not be obtained. The correct adjustment of
the relay consists of properly balancing the pull of the spring on the
armature against the pull of the magnetic force developed when current
flows through the relay. The best adjustment for any condition is that
which gives satisfactory operations with the smallest values of GAP and
SPRING pointer settings. Therefore, for all adjustments, obtain the
smallest GAP pointer setting which will allow the relay to operate and
the smallest spring pointer setting that will open the contacts sharply. To
adjust the relay with the telegraph set connected to a line, follow the
procedure outlined below.

(1) Place the headset plug across the line terminals with the tip of
the plug touching one terminal and the sleeve the other, to determine if
another station is using the line. If a station is transmitting, clicks will
Jbe heard in the receiver.

{"'f^j^riL^ Original from

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(2) If the line is free, place the plug in the jack.

(3) Set the SPRING and GAP pointers to indicate 0.

(4) Press the key, hold the receiver to the ear, and slowly move the
GAP pointer until tone is heard in the receiver.

(5) Release the key. If the tone does not stop, increase the SPRING
pointer setting until the tone stops.

(6) If the tone still does not stop when the SPRING pointer is moved
to its highest setting, increase the GAP setting slightly, return the
SPRING pointer to zero, and again increase the SPRING pointer set-
ting until the tone stops.

(7) Call the most distant station on the line and request it to trans-
mit for testing.

(8) If the distant station's transmission fails to actuate the relay,
proceed as described in paragraph 16.

(9) Call any other stations on the line, and, if necessary, make further
adjustments of the relay.

c. Relay BK-7-B. No adjustment of the armature gap is provided
on Relay BK-7-B. When the ADJUST pointer is set at 0, the armature
spring tension is at a minimum and approximately 0.2 milliamperes as
required to operate the relay. If, however, a stronger current flows
through the relay winding, the spring tension will not be strong enough
to break the contacts quickly after the current ceases to flow and clear
signals will not be obtained. The best possible adjustment is one which
will give satisfactory operation with the smallest ADJUST pointer set-
ting. To adjust the relay with the telegraph sets connected to the line
follow the procedure outlined below.

(1) Test for a clear line as described in b(\) and (2) above.

(2) Set the ADJUST pointer to on the dial.

(3) Depress the key and hold the receiver to the ear; tone should be
heard in the receiver.

(4) Increase the ADJUST pointer setting until the tone stops.

(5) Alternately press and release the key while holding the receiver
to the ear to determine if the signals stop sharply when the key is released.

(6) If the signals do not stop sharply when the key is released, increase
the ADJUST pointer setting until they do.

(7) Proceed as described in fe(7), (8), and (9) above.

16. Additional Line Battery

If, by placing the tip and sleeve of the headset plug across the line ter-
minals LI and L2, it is determined that a distant station is transmitting
and the relay cannot be adjusted as described in paragraph 15 to give
satisfactory operation, proceed in the following manner:

a. Add another Battery BA-2 in series with the one already in the set.

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§ uigitizeo by vjuugn UNIVERSITY OF CALIFORNIA

b. Call the distant station and inform it that the line battery has been
increased to 45 volts. Request the distant station to increase its line battery
to the same value and to transmit for further test.

c. Adjust the relay as described in paragraph 15.

d. If satisfactory operation still cannot be obtained, add a third Bat-
tery BA-2 in series with the other two and repeat the procedure given
in b and c above.

Caution: It is possible to cause serious damage to the set by adding
an excessive amount of line battery. If the keys of two or more sets are
depressed simultaneously, the combined voltage of all the batteries in
the sets will be impressed upon the series circuit containing all the relays.
Add only enough voltage to assure satisfactory operation, and no more.

17. Operation

a. Transmitting. Operate the key in accordance with instructions
given in TM 11-459.

b. Receiving. During reception, use may be made of either the bell
or interrupter contained in the telegraph set. If use of the bell is desired,
remove the headset plug from the jack.

c. Break-in. If during reception it is desired to break in on the trans-
mission, slowly depress and release the key. This action will cause faulty
operation of the relay at the transmitting station and will indicate to the
operator that a break-in is desired.

d. Continuous Operation. If the set is to be operated continuously,
keep the headset plugged into the telegraph set. Call signals are then
received only in the headset, which must be worn to prevent missing a call.

e. Stand-by Operation. Remove the headset plug from the jack.
Call signals will then be indicated by the ringing of the bell.

Section VI. EQUIPMENT PERFORMANCE CHECK SHEET

1 8. Purpose and Use of Equipment Performance Check Sheet

a. General. The equipment performance check sheet (par. 19) will
help the operator to determine whether Telegraph Set TG-5-(*) is
functioning properly. The check sheet gives the item to be checked, the
conditions under which the item is checked, the normal indications, and
the corrective measured that the operator can take. Items 1, 2, and 3
are performed when preparing the equipment for use, items 4, 5, and 6
are checked when starting, items 7 and 8 during operation, and items 9
and 10 when stopping operation. Items 7 and 8 should be checked at least
once during a normal operating period or at least four times each day
during continuous operation.

> ri^inl^* Original from

Digitized by ^UU^ll UNIVERSITY OF CALIFORNIA

■ ^

b. Action. Information given in the action or condition column
represents an action that must be taken in order to check the indications
given in the normal indications column.

c. Normal Indications. The normal indications listed include the
visible and audible signs that the operator will perceive when he checks
the items listed. If the indications are not normal, the operator should
apply the recommended corrective measures.

d. Corrective Measures. The corrective measures listed are those
that the operator can make without turning the equipment in for repairs.
Reference to item five in the table indicates that the correction of the
trouble cannot be effected during operation and that trouble shooting
by an experienced repairman is called for. If the set is completely inoper-
ative, or if the recommended corrective measures do not yield results,
trouble shooting is necessary. However, if the tactical situation requires
that communication be maintained, and if the set is not completely inoper-
ative, the operator must maintain the set in operation as long as it is
possible to do so.

19. Equipment Performance Check Sheet

Item
No.

Item

Action or condition

Normal indication

Corrective measure

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Cu
U

2.
3.

Batteries
BA-30

Batteries
BA-2

Line

Install batteries
in rear compart-
ment.

Install in top bat-
tery compart-
ment.

Connect line to
terminals LI
and L2.

<
H

5.
6.

Relay

Transmitting
circuit.

Receiving
circuit.

Insert headset
plug in jack.
Alternately de-
press and re-
lease key.

Call distant
station.

Distant station
transmitting.

Tone heard in re-
ceiver when
key is depressed
and not when
released.

Distant station
answers.

Signals heard in
receiver.

Adjust relay.
(See par. 15.)

See paragraph
16.

Adjust relay
(par. 15). See
paragraph 16.

7.
8.

Transmitting
circuit.

Receiving

Key operated.
Key unoperated.

Transmission
possible to
distant station.

Reception
possible from
distant station.

Check batteries.
Check batteries.

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Original from
UNIVERSITY OF CALIFORNIA

item

No.

Item

Action or condition

Normal indication

Corrective measure

9.
10.

Batteries.
Line

Remove batteries,
Disconnect line.

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Original from
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PART THREE
PREVENTIVE MAINTENANCE

Section VII. PREVENTIVE MAINTENANCE TECHNIQUES
20. Meaning of Preventive Maintenance

Preventive maintenance is a systematic series of operations performed at
regular intervals on equipment to eliminate major break-downs and
unwanted interruptions in service, and to keep the equipment operating at
top efficiency. To understand what is meant by preventive maintenance,
it is necessary to distinguish between preventive maintenance, trouble
shooting, and repair. The primary function of preventive maintenance
is the prevention of break-downs and, therefore, the need for repair. The
primary function of trouble shooting and repair is the location and cor-
rection of existing defects. The importance of preventive maintenance
cannot be overemphasized. The entire system of wire communication
depends upon each set being in operation when it is needed and also upon
its operating efficiency.

Note. The operations in section VII are considered first- and second-echelon (organi-
zation operators and repairmen) maintenance.

21* Description of Preventive Maintenance Techniques

a. General. Most of the parts used in Telegraph Set TG-5-(*) require
routine preventive maintenance. Those requiring maintenance differ in
the amount and kind required. Because hit-or-miss maintenance techniques
cannot be applied, definite and specific instructions are needed. This
section of the manual contains these specific instructions and serves as
a guide for personnel assigned to perform the six basic maintenance
operations : Feel, Inspect, Tighten, Clean, Adjust, and Lubricate. Through-
out this manual the following lettering system will be used for the six
operations :

F— Feel*

I — Inspect
T— Tighten
C — Clean
A — Adjust
L — Lubricate*

The first two operations establish the need for the other four. The selec-
tion of operations is based on the general knowledge of field needs. For

* The feel and lubricate operations are not applicable to Telegraph Set TG-5-C*).

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example, dust encountered on dirt roads during cross-country travel
filters into the equipment no matter how much care is taken to prevent it.
Rapid changes in weather (such as heavy rain followed by blistering heat) ,
excessive dampness, snow, and ice tend to cause corrosion of exposed
surfaces and parts. Without frequent inspections and the performance
of necessary tightening, cleaning, and lubricating operations, equipment
becomes undependable and subject to break-down.

b. Feel. The feel operation is used most often to check for overheating.

c. Inspect. Inspection is the most important operation in the preventive
maintenance program. A careless observer will overlook the evidences of
minor trouble. Although these minor defects may not interfere with the
performance of the equipment, valuable time and effort can be saved if
they are corrected before they lead to major break-downs. Make every
effort to become thoroughly familiar with the indications of normal
functioning, in order to be able to recognize the signs of defective equip-
ment. Inspection consists of carefully observing all parts of the equipment,
noticing their color, placement, state of cleanliness, etc. Inspect for the
following conditions :

(1) Overheating, as indicated by discoloration, blistering, or bulging
of the parts or surface of the container ; leakage of insulating compounds ;
and oxidation of metal contact surfaces.

(2) Placement, by observing that all leads and cabling are in their
original positions.

(3) Cleanliness, by carefully examining all recesses in the units for
accumulations of dust, especially between connecting terminals. Parts,
connections, and joints should be free of dust, corrosion, and other foreign
matter. In tropical and high-humidity locations, look for fungus growth
and mildew.

(4) Tightness, by testing any connection or mounting which appears to
be loose.

d. Tighten, Clean and Adjust. These operations are self-explan-
atory. Specific procedures for performing them are given in paragraphs 23
through 34 whenever necessary.

Caution: Screws, bolts, and nuts should not be tightened carelessly.
Fittings tightened beyond the pressure for which they are designed will
be damaged or broken. Whenever a loose connection is tightened, moisture-
proof and f ungiproof it again by applying the varnish with a small brush.

See section X for details of moistureproofing and fungiproofing.

e. Lubricate. Lubrication means the addition of oil or grease to form
a film between two surfaces that slide against each other, in order to
prevent mechanical wear from friction.

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5> ment

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en

22. Common .Materials Needed

Note. The tools and materials listed below must be at hand before starting the pre-
ventive maintenance procedures.

The following is a list of the tools and materials needed for performing
preventive maintenance operations on Telegraph Set TG-5-(*).

Long-nose pliers.

Diagonal pliers.

Z l / 2 inch cabinet screw driver.

Solvent, Dry Cleaning, Federal spec No. PS-661a.

Burnisher Signal Corps stock No. 4A2805A/5.

Neat's-foot oil.

Bristle brushes.

Saddle soap.

Cleaning cloths.

Crocus cloth.

Note. Gasoline will not be used as a cleaning fluid for any purpose. Solvent, dry-
cleaning, is available as a cleaning fluid through established supply channels. Oil, fuel,
diesel, may be used for cleaning purposes when dry-cleaning solvent is not on hand.
Carbon tetrachloride will be used as a cleaning fluid only where specified for cleaning
contact parts of electrical equipment, or as specified where inflammable solvents can-
not be used because of the fire hazard. Oil, fuel, diesel, will not be used for cleaning
electrical contacts.

23. Box, Exterior

a. Inspect (I). Inspect the box for damaged places, dirt, dust, rust,
corrosion, and loose, damaged, or missing screws.

b. Tighten (T). With a suitable screw driver, tighten all screws
snugly.

c. Clean (C). With a clean, dry cloth, wipe all dirt and dust off the
box.

Note. In order to perform the preventive maintenance operations contained in the
following paragraphs, it will be necessary to open the box and rear battery compart-

24. Rear Battery Compartment

a. Inspect (I). Inspect the battery compartment for dirt, dust, cor-
rosion, and loose or missing battery contact springs.

b. Clean (C). With a soft bristle brush, remove all dirt, dust, and
foreign matter from the battery compartment. Carefully clean the battery
contact springs with crocus cloth to insure good electrical connections.

25. Line Battery Compartment

a. Inspect (I). Inspect the battery compartment for dirt, dust, and
other foreign matter.

b. Clean (C). With a soft bristle brush, remove all dirt, dust, and
foreign matter.

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§ Uigmzeo Dy\jUU^lL UNIVERSITY OF CALIFORNIA

26. Terminal Block

a. Inspect (I). Inspect the terminal block for cracks, chips, or breaks.
Check for loose and damaged terminals. Inspect the terminal block and
terminals for dirt, dust, and corrosion. Check for loose connections.

b. Tighten (T). Tighten all loose terminals and loose connections.

c. Clean (C). Remove all dirt, dust, and foreign matter on the ter-
minal block and terminals, using a soft bristle brush.

27. Receiver R-3

a. Inspect (I). Inspect the receiver for dirt, dust, and chipped,
cracked, or broken places. Inspect the exterior only. Inspect the head-
band for tears or frayed edges.

b. Clean (C). Wipe all dirt, dust, and other foreign matter from the
receiver with a clean, dry cloth.

28. Cord CC-335

a. Inspect (I). Inspect the cord for dirt, dust, oil, grease, and dam-
aged or broken insulation. Examine the cord, where it enters the receiver,
for worn or frayed insulation.

b. Clean (C). Wipe off all dust and dirt using a clean, dry cloth.
If it becomes necessary to remove oil or grease, use dry-cleaning solvent.

29. Plug PL-55

a. Inspect (I). Inspect the plug for bent or broken parts. Check for
an accumulation of dust and dirt.

b. Clean (C). Wipe off the plug with a clean rag moistened in dry-
cleaning solvent.

30. Case CS-49-(*)

a. Inspect (I). Inspect the case for torn or frayed portions. Check

for breaks or cracks in the leather corners and bottom. Inspect the snap

fastener to see that it is mounted firmly in the case.

b. Clean (C). With a clean, dry cloth wipe all dirt and dust off the
case. Use saddle soap and neat's- foot oil to clean the leather portions
of the case. Wash the strap with soap and water.

31. Interrupters BZ-5-(*) and BZ-7-(*)

a. Inspect (I). Inspect the external portion of the interrupter for
accumulations of dirt, dust, and other foreign matter. Check for dents,
cracks, and breaks in the case. Check for loose connections.

{"'rtj-iril f* Original from

by\jUU^IL UNIVERSITY OF CALIFORNIA

b. Tighten (T). Tighten all loose connections.

c. Clean (C). Clean the external portion of the case with a soft
bristle brush.

32. Relays BK-7-A and BK-7-B

a. Inspect (I). Inspect the relay case for accumulation of dirt and
dust. Check to see that there are no chipped or broken parts. Inspect
the relay contacts for pitted or worn places. Inspect the metal cover on
Relay BK-7-B for bent portions and see that it is in place.

b. Clean (C). Clean the exterior of the case with a clean, dry cloth.
Carefully burnish the relay contacts with the burnisher furnished with
the telegraph set. Place the burnisher between the contacts and press
the contacts together lightly with the tips of the fingers. Move the
burnisher back and forth until the contacts are clean and smooth.

c. Adjust (A). Adjust the contacts as described in paragraph 15
when putting the set back into operation.

Note. The contacts of Relay BK-7 cannot be burnished without removing the relay
from the set. This procedure is covered in section XI.

33. Bell

a. Inspect (I). Inspect the exterior portion of the bell for dirt, dust,
rust, and other foreign matter. Remove the bell cover and check the con-
tacts for pitted or worn spots. Check for loose connections.

b. Clean (C). Carefully remove all dirt, dust, and other foreign
matter on the bell, using a soft bristle brush. Be careful not to disconnect
or damage any of the wiring. Burnish the contacts with a contact bur-
nisher. Place the burnisher between the contacts and move it back and
forth until the contacts are smooth and bright.

34- KeyJ-41-{*)

a. Inspect (I). Inspect the key for broken or worn parts. Check for
loose connections. Inspect the key for missing parts.

b. Tighten (T). Tighten all loose screws except those used for adjust-
ments. Tighten all loose connections.

c. Clean (C). Clean all dirty or worn contacts with a contact bur-
nisher. Place the contact burnisher between the contacts. Press the con-
tacts together by exerting a light pressure on the key lever. Move the
burnisher back and forth until the contacts are clean and bright.

d. Adjust (A). Adjust the key, before operation, as described in
paragraph 14.

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26
Section VIII. PREVENTIVE MAINTENANCE CHECK LIST

35. Preventive Maintenance Check List

a. For ease and efficiency of performance, preventive maintenance on

Telegraph Set TG-5-(*) will be broken down into daily, weekly, and

monthly items.

Note. The time intervals for performing the preventive maintenance outlined in
the preceding paragraphs and the check list may be reduced at any time by the local
commander. However, for best performance of the equipment, perform the operations
at least as frequently as called for in the check list.

b. The general techniques involved and application of FITCAL oper-
ations in performing preventive maintenance on individual parts are dis-
cussed in section VII. These general instructions are not repeated in
this section. Personnel performing preventive maintenance will refer
to section VII when more detailed information is required on the items
listed in the following schedule. After preventive maintenance has been
performed on a given day, the equipment will be put into operation and
checked for satisfactory performance.

Operation

Description

When performed

Item

Daily

Weekly

Monthly

Echelon

I.T, C
I, c

I.C

I.T.C
I, c
I, c
I, c
I.C
I.T.C

I.C, A

i.c

I.T.C.A

Box, exterior (par. 23)

*
*
*

*
*

1st

4
5
6
7

Rear battery compartment

(par. 24).
Line battery compartment

(par. 25).

Terminal block (par. 26)

Receiver R-3 (par. 27)

Cord CC-335 (par. 28)

Plug PL-55 (par. 29)

1st

1st
1st
1st
1st

8
9

Case CS-49-(*) (par. 30)

Interrupters BZ-5-(*) and

BZ-7-(*) (par. 31).
Relays BK-7-A and BK-7-B

(par. 32).
Bell (par. 33)

1st
1st

Key J-41-(*) (par. 34)

F* I T C A

Feel Inspect Tighten Clean Adjust

* The feel and lubricate operations are not applicable to Telegraph Set TG-5-(*).

L*
Lubricate

Section IX. LUBRICATION

Lubrication of this equipment is not required.

Section X. MOISTUREPROOFING AND FUNGIPROOFING
36. General

When operated in tropical areas where temperature and relative humidity
are extremely high, Signal Corps equipment requires special attention.
These are some of the problems met:

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a. Capacitors, coils, etc., fail because of the effects of fungus growth
and excessive moisture.

b. Electrolytic action, often visible in the form of corrosion, takes
place in coils, etc., causing eventual break-down.

c. Hook-up wire insulation and cable insulation break down. Fungus
growth accelerates deterioration.

d. Moisture forms electrical leakage paths on terminal blocks and
insulating strips, causing flash-overs and crosstalk.

e. Moisture provides leakage paths between battery terminals.

37. Treatment

A moistureproofing and fungiproofing treatment has been devised which,
if properly applied, provides a reasonable degree of protection against
fungus growth, insects, corrosion, salt spray, and moisture. The treat-
ment involves the use of a moisture- and fungi-resistant varnish applied
-with a spray gun or brush. See TB SIG 13 for a detailed description
of the varnish-spray method of moistureproofing and fungiproofing and
the supplies and equipment required in this treatment.

Caution: Varnish spray may have poisonous effects if inhaled. To
avoid inhaling spray, use respirator if available ; otherwise, fasten cheese-
cloth or other cloth material over nose and mouth. Never spray varnish
or lacquer near an open flame. Do not smoke in a room where varnish
or lacquer is being sprayed. The spray may be highly explosive.

38. Telegraph Set TG-5-(*)

a. Preparation. Make all repairs and adjustments necessary for the
proper operation of the equipment.

b. Disassembly. (1) Raise the cover of the telegraph set and open
the front panel.

(2) Remove the bell and disconnect the attached leads.

(3) Remove the two screws which hold the jack mounting to the right
side of the case, and pull jack forward. Do not disconnect the wiring.

(4) Remove the screws from the binding post mounting plate and
expose the back of the plate. Do not disconnect the wiring.

(5) Remove Battery BA-2 from the line battery compartment.

(6) Open the door to the rear battery compartment and remove the
two Batteries BA-30. The batteries are not to be treated.

c. Cleaning. Clean all dirt, dust, rust, fungus, oil, grease, etc., from
the equipment to be processed.

d. Masking (fig. 21). Cover the following parts with masking tape:

(1) Telegraph key.

(2) Spring and key contacts of jack.

f™' f\j~ifi|f> Original from

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Figure 21. Telegraph Set TG-5-A disassembled and masked.

(3) Openings in relay cover base, and adjusting arm.

(4) Binding post wiring slots.

(5) Terminals of leads disconnected from bell.

(6) Battery contacts in rear battery compartment.

e. Drying, Place all equipment, except the batteries, in an oven or
under heat lamps and dry for 2 to 3 hours at 160° F. Do not apply heat
to the batteries.

/. Varnishing. (1) Apply three coats of moistureproofing and fungi-
proofing varnish (Lacquer, Fungus-resistant, spec No. 71-2202 (stock
No. 6G1005.3), or equal, with a spray gun. Allow each coat to air-dry
for IS to 20 minutes before applying the next coat,

(2) Apply varnish immediately after the equipment is dried. If var-
nish is not applied immediately, moisture condenses on the equipment.
Varnish applied over the moisture peels off readily after the varnish has
dried.

(3) Remove the cover from the bell and varnish the coils, using a
brush.

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g. Reassembly. (1) Remove all masking tape being careful not to
peel varnish from nearby areas.

(2) Reassemble the telegraph set and test its operation.

h. Marking. Mark the letters MFP and the date of treatment near
the nameplate on cover.

Example: MFP— 3 Feb 45.

39. Moistureproofing and Fungiproofing After Repairs

If, during repair, the coating of protective varnish has been punctured
or broken, and if complete treatment is not needed to reseal the equip-
ment, apply a brush coat to the affected part. Be sure the break is com-
pletely sealed.

f™' f\j~ifiL:> Original from

Digitized by ^UU^IL UNIVERSITY OF CALIFORNIA

PART FOUR
AUXILIARY EQUIPMENT

(NOT USED)

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§ uigitized by v^uugii UNIVERSITY OF CALIFORNIA

PART FIVE
REPAIR INSTRUCTIONS

Note. Failure or unsatisfactory performance of equipment used by Army Ground
Forces and Army Service Forces will be reported on WD AGO Fcrm 468 (Unsatis-
factory Equipment Report) ; by Army Air Forces, on Army Air Fcix:s Form 54
(unsatisfactory report). If either form is not available, prepare the data according to
the sample form reproduced in figure 41.

Section XI. THEORY OF TELEGRAPH SET TG-5-(*)

40. Circuit Elements

A. Receiver. The receiver is of the magnetic type. It consists of two
coils, connected in series, wound on the pole pieces of a permanent magnet
mounted in a watch type case. The resistance of the coil windings is
approximately 80 ohms. A thin metal diaphragm is placed immediately
over the pole pieces of the magnet and is held in place by a screw cap
which serves as an earpiece and protects the inside of the case from
dust and dirt. Cord CC-335 is fastened by screw type terminals to the
ends of the coil inside the case and the opposite end of the cord is
terminated in Plug PL-55.

b. Receiver Jack. The receiver jack consists of two fixed and two
movable contacts mounted on a metal frame which, in turn, is mounted
on a phenolic block fastened to the box. In the normal position the two
bottom contacts are closed and the top contacts open. When the plug is
inserted in the jack the tip spring is forced up, opening the bottom set
of contacts and closing the top set of contacts.

c. Capacitor CA-210. The capacitor consists of two 0.25 microfarad
units inclosed in a metal can. Leads for each section are brought out
separately.

d. Bell. The bell contains two coils of wire, connected in series, and

mounted side by side on the bell frame. The total resistance of the coils
is approximately 16 ohms. A soft-iron armature is mounted directly over
the coils. One end of this armature is pivoted on the bell frame, and
the other end is provided with a metal clapper. Two contacts are pro-
vided, one mounted on the armature and the other fastened to the bell
frame. In the normal position these two contacts are closed. When direct
current is applied to the bell terminals, current flows through these con-
tacts and through the coils. Current flowing through the coils produces
a magnetic field which attracts the armature and opens the contacts.

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When the contacts open, current ceases to flow through the coil, the
armature returns to its normal position, and the contacts close, allowing
current to flow, and the cycle repeats. This movement of the armature
causes the clapper to strike the gong and a ringing sound results.

e. Interrupter. The interrupter consists of a carbon button trans-
mitter mounted against the diaphragm of a magnetic type receiver and
wired in series with it. When direct current flows through the receiver
section, the receiver diaphragm is attracted toward the receiver pole
pieces. Since this diaphragm is mounted directly against the transmitter
button, the button moves with it and causes an increase in the trans-
mitter resistance. . This increase in resistance causes a reduction in the
amount of current flowing through the receiver which allows the dia-
phragm to move outward. When the diaphragm moves outward it presses
against the transmitter button, reduces the resistance of the transmitter,
and again allows more current to flow through the receiver. This action
repeats itself as long as the interrupter is connected in the circuit.

/. Relay BK-7 and BK-7-A. Relay BK-7 and BK-7-A consist of
a coil of wire, a movable horseshoe shaped core, two fixed, and one mov-
able contact mounted inside a phenolic case. The coil is wound on a
phenolic bobbin and the ends connected to a terminal strip mounted on
the end of the relay case. The resistance of the coil in Relay BK-7 is
150 ohms and in Relay BK-7-A, 600 ohms. One leg of the core slides
inside the coil and the opposite leg passes outside the bottom of the coil.
A small rack is screwed to this leg approximately at its center. This
rack meshes with a pinion gear mounted on a shaft passing through
the sides of the relay case. Movement of a pointer fastened to this shaft
outside the relay case causes the pinion gear to rotate, which in turn
moves the core. The relay contacts are mounted directly in front of the
end of the core. A movable contact is pivoted at its center and the bot-
tom is fastened to a small spring. The opposite end of this spring is
fastened to a piece of string, which in turn is fastened to a shaft pass-
ing through the sides of the relay case. When the shaft is turned by
a pointer fastened to it on the outside of the case, the spring tension
on the movable contact is increased or decreased accordingly. There-
fore, by adjustment of these two levers the gap between the movable
contact and the core, and the spring tension on the contact, can be
adjusted. The two fixed contacts are mounted to the relay case by means
of a screw through the contact near the bottom end. The distance between
these two contacts and the movable contact can be adjusted by two screws
threaded through the end of the relay case. These two fixed contacts are
connected to the terminal strip on the end of the relay by flat metal con-
ductors. The movable contact is connected by a flexible wire to a solid
conductor which terminates at the terminal strip.

g. Relay BK-7-B. Relay BK-7-B is constructed in the same man-

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ner as Relay BK-7 and BK-7-A except that the core of the relay wind-
ing remains in a fixed position and no provisions are made for the
adjustment of the air gap between the movable contact and the core.
The resistance of the relay winding in Relay BK-7-B is 4,400 ohms.

41 • Theory of Operation

a. Line Circuit. (1) The L2 binding post, relay winding, key, and
LI binding post are connected in series, and form the line circuit.

(2) Incoming current, flowing through terminal L2, the relay wind-
ing, rear contact of the key, and out through terminal LI, operates the
relay, thereby closing a local circuit in the set. (See figs. 22 and 23.)

IS SYMBOL FOR FIXED CAPACITOR

TLS2787-S

Figure 22. Line circuit, Telegraph Set TG-5.

(3) Outgoing current is furnished by a 22 J/2 -volt battery (Battery
BA-2) which is connected in series with the front contact of the key
and terminal LI. Depressing the key closes the circuit to the battery and
allows current to flow through the key lever and front contact of the
key, the relay winding, over the line, and back to the battery. (See figs.
24 and 25.)

(4) Sparking between the contacts of the key, caused by the mag-
netic field surrounding the relay breaking down through the winding,
is suppressed by placing a 0.25 microfarad capacitor in parallel with
the contacts. (See figs. 24 and 25.)

b. Local Circuits. (1) The bell, or signaling circuit, consists of the
bell, relay contacts, 3- volt d-c supply, and the break contacts of the jack.

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Original from
UNIVERSITY OF CALIFORNIA

Ml*Y BK-7-W) (SEE NOTE)

r£

0.2SMF

]"» I

V |

0.25MF

<-;

INTERRUPTER pv

BZ-7-1*)

BELL I6JI

Juaju

Hi|

&=n

RECEIVER
R-3

CORO CC-33S

JACK JK-35 PLUG

PL -35

NOTE: RESISTANCE OF RELAY BK-7-A IS 600A
RESISTANCE OF RELAY BK-7-B IS 4,400-*!

ZjZ IS SYMBOL FOR FIXED CAPACITOR
I # Tl5*78*-S

Figure 23. Line circuit, Telegraph Sets TG-5-A and TG-5-B.

The parts are wired in series, and are controlled by the operation of the
relay in the line circuit. (See figs. 26 and 27.)

(2) The interrupter circuit consists of the interrupter, make contact
of the jack, and a 3-volt d-c supply. Inserting the plug of the headset
in the jack closes the make contact, opens the bell circuit, and puts the
interrupter in operation. (See figs. 28 and 29.)

J JACK JK-35 PLUG

IS SYMBOL FOR FIXED CAPACITOR

TLS2789-*

Figure 24. Transmitting circuit, Telegraph Set TG-5.

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Original from
UNIVERSITY OF CALIFORNIA

RELAY BK-T-W) (SEE NOTE)

rtf

0.25MF

KEY

_Jle Ju

a I

Ulihf

0.25MF

INTERRUPTER pi

BZ-7-H0

BELL I6JL

-22

HiH

RECEIVER
R-3

CORO CC-335

JACK JK-35 PLUG

PL- 33

NOTE: RESISTANCE OF RELAY BK-7-A IS 600A
RESISTANCE OF RELAY BK-7-B IS 4,400.0.

T""*" IS SYMBOL FOR FIXEO CAPACITOR
Tl_5£790-$

Figure 25. Transmitting circuit, Telegraph Sets TG-5-A and TG-5-B.

(3) The receiving circuit consists of the Receiver R-3, plug, jack,
and relay contacts, and a 0.25 microfarad capacitor connected in series
and the combination connected in parallel with the interrupter. When
the relay contacts are closed, the varying voltage across the interrupter
is impressed across the receiver causing a tone of approximately 1,000
cycles to be heard in it. Shorting of the battery in the interrupter circuit
by the receiver is prevented by the capacitor in series with the receiver.

IS SYMBOL FOR FIXED CAPACITOR

PLUS
PL- 53

TL9179I-*

Figure 26. Signaling circuit, Telegraph Set TG-5.

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RELAY BK-7-GK) (SEC NOTE)

J JACK JK-55 «J£

NOTE: RESISTANCE OF RELAY BK-7-A IS 600A
RESISTANCE OF RELAY BK-7-B IS 4,400.0.

IS SYMBOL FOR FIXEO CAPACITOR

Figure 27. Signaling circuit, Telegraph Sets TG-5-A and TG-5-B.

Section XII. TEST EQUIPMENT

42. General

A voltohmmeter is the only test equipment normally required for field
maintenance of Telegraph Set TG-5-(*). Two voltohmmeters which
are available in the field are Voltohmmeter 1-166 and Test Set
TS-26/TSM.

LI 22V

HHWtH

RELAY BK-7
I50A

0.25MF

K E vL

RECEIVER
R-3

CORO CC-J3S

° — ofc

J JACK JK-35 PLUG

1 PL- 55

IS SYMBOL FOR FIXEO CAPACITOR

Tc5*m-«

Figure 28. Interrupter circuit, Telegraph Set TG-5.

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Original from
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RELAY BK-7-W0 (SEE NOTE)

JACK JK-35 /«-UG

PL- 55

NOTE: RESISTANCE OF RELAY BK-7-A IS 600 A
RESISTANCE OF RELAY BK-7-B IS 4,400.0.

IS SYMBOL FOR FIXED CAPACITOR

*-p _ .. ?L52?t#-S

Figure 29. Interrupter circuit, Telegraph Sets TG-5-A and TG-5-B.

Caution: Before using a voltohmmeter for checking resistances in
Telegraph Set TG-5-(*), always remove the batteries from the tele-
graph set to prevent damage to the voltohmmeter.

43. Voltohmmeter 1-166

This test set is contained in Test Equipment IE-29. Voltohmmeter 1-166
can be used for making continuity, voltage, and resistance measurements.

IS SYMBOL FOR FlXEO CAPACITOR

PLUG
PL- 55

TL5Z795-S

Figure 30. Receiving circuit, Telegraph Set TG-5.

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Original from
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JtELAY BK-7-1*) (SEE MOTE)

-J I JACK JK- 35 PLUG

fNOTE* RESISTANCE OF RELAY BK-7-A IS 600 A
RESISTANCE OF RELAY BK-7-B »S 4,400-0.

fc IS SYMBOL FOR FIXED CAPACITOR TL52796-S

Figure 31. Receiving circuit, Telegraph Sets TG-5-A and TG-5-B.

Figure 32. Voliohmmeter 1-166.

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UNIVERSITY OF CALIFORNIA

For operation and use of Voltohmmeter 1-166, see TM 11-2613.

44. Test Set TS-26/TSM

This test set can be used for making continuty, voltage, and resistance
measurements. For operation and use of Test Set TS-26/TSM, see
TM 11-2017.

Figure 33. Test Set TS-26/TSM.

Section XIII. TROUBLE SHOOTING

45. General

No matter how well equipment is designed and manufactured, faults

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occur in service. When such faults occur, the repairman must locate and
correct them as rapidly as possible. This section contains general infor-
mation to aid personnel engaged in the important duty of trouble shooting.

a. Trouble-shooting Data. Take advantage of the material supplied
in this manual to help in the rapid location of faults. Consult the follow-
ing trouble- shooting data when necessary:

(1) Trouble-shooting chart. (See par. 49.)

(2) Complete schematic diagrams. (See figs. 34 and 35.)

(3) Resistance data for all terminals. (See par. 48.)

(4) Illustrations of components which aid in locating or identifying
parts. (See figs. 3, 4, 5, and 6.)

ft. Trouble-shooting Steps. First analyze the trouble report to deter-
mine the probable cause of the trouble. When analyzing the trouble
report, use the schematic diagram to localize the fault to a particular
component. Make a complete visual inspection of the wiring and con-
nections to the associated equipment. If no wires or connections are
broken, the trouble must be located by making' continuity and resistance
measurements. By following the circuit with a systematic process of
elimination, the fault can usually be located in the shortest possible time.
Start at a point where the circuit is known, from the analysis, to be
good, and proceed step-by-step, eliminating parts of the circuit until the
fault is located.

46. Line and Bell Circuit

a. Procedure. (1) Short the line terminals LI and L2 with a screw
driver or a short piece of wire.

(2) Alternately depress and release key.

b. Normal Indications. (1) Relay is heard operating.

(2) Bell rings when key is depressed and stops when key is released.

c. Indications, Probable Causes, and Remedies of Trouble.

(1) Relay does not operate and bell does not ring when key is depressed,
(o) Dirty key contacts. Burnish contacts. (See par. 34.)
(6) Dead Battery BA-2. Replace battery. (See par. 9.)
(c) Defective relay. Adjust or replace relay. (See pars. 15, 16, and 56.)
(rf) Defective wiring. Check and repair wiring.
(2) Relay operated but bell does not ring when key is depressed.

(a) Dead Batteries BA-30. Replace batteries. (See par. 9.)

(b) Bell contacts out of adjustment. Adjust contacts. (See par. 14b.)

{"'rtj-iril f* Original from

Digitized by ^UU^IL UNIVERSITY OF CALIFORNIA

(d) Defective bell. Replace bell. (See par. 54.)
(r) Defective wiring. Check and repair wiring.

(3) Relay operates and bell rings when key is depressed. Bell con-
tinues to ring when key is released.

(a) Key contacts not opening fully. Adjust key. (See par. 14a.)

(b) Relay out of adjustment. Adjust relay. (See pars. 15 and 16.)

(4) Bell rings when shorting wire is placed across terminals LI and
L2 before key is depressed.

(a) Relay out of adjustment. Adjust relay. (See pars. 15 and 16.)

(b) Capacitor shorted. Replace capacitor. (See par. 55.)

47. Transmitting and Receiving Circuit

a. Procedure. (1) Short line terminals LI and L2 with a screw driver
or a short piece of wire.

(2) Insert headset plug in jack.

(3) Alternately depress and release key.

b. Normal Indications. (1) Relay is heard operating.

(2) Loud tone heard in receiver when key is depressed. Tone stops
when key is released.

c. Indications, Probable Causes, and Remedies of Trouble.
(1) Relay does not operate. No tone heard in receiver.

(a) Dirty key contacts. Clean key contacts. (See par. 34.)

(b) Dead Battery BA-2. Replace battery. (See par. 9.)

(2) Relay operates. No tone heard in receiver.

(a) Dead Battery BA-30. Replace batteries. (See par. 9.)

(b) Relay out of adjustment. Adjust relay. (See pars. 15, 16, and 56.)

(d) Defective headset. Replace headset.

(e) Defective capacitor. Replace capacitor. (See par. 55.)

(/) Defective wiring. Check and repair wiring.

(3) Relay operates and tone is heard in receiver when key is depressed.
Tone continues when key is released.

(a) Key contacts not opening fully. Adjust key. (See par. 14a.)

(b) Relay out of adjustment. Adjust relay. (See pars. 15 and 16.)

(4) Tone heard in receiver as soon as terminals LI and L2 are shorted
and before the key is depressed.

(a) Relay out of adjustment. Adjust relay. (See pars. 15 and 16.)

(b) Capacitor shorted. Replace capacitor. (See par. 55.)

{"'rtj-iril f* Original from

Digitized by ^UU^IL UNIVERSITY OF CALIFORNIA

48. Circuit Measurements

a. General. If, after making the repairs suggested in the preceding
paragraphs, satisfactory operation of the telegraph set still cannot be
obtained, or trouble is traced to circuit wiring, measure the resistance
of various parts of the circuit between the points indicated in the fol-
lowing chart. If any of the resistances obtained differ materially from

D=n

RECEIVER
R-3

CORO CC-335

, v| _

I JACK JK-35 PLUG

PL- 53

IS SYMBOL FOR FIXEO CAPACITOR

U&2799-S

Figure 34. Circuit diagram, Telegraph Set TG-5.
RELAY BK-7-(*) (SEE NOTE)

tPn

RECEIVER
R-3

CORO CC-335

4°-=dj

JACK JK-35 JJt.UG

PL* 53

NOTE: RESISTANCE OF RELAY BK-7-A IS 600 A
RESISTANCE OF RELAY BK-7-B IS 4,400 A

i IS SYMBOL FOR FIXEO CAPACITOR > mm

I TL53800-S

Figure 35. Circuit diagram. Telegraph Sets TG-S-A and TG-5-B.

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UNIVERSITY OF CALIFORNIA

those given in the chart, check the wiring of that portion of the circuit
against the circuit diagrams (figs. 34 and 35) and the wiring diagram
in the cover of the telegraph set.

b. Resistance Chart.

Between
(points of measurement)

Resistance
(ohms)

Telegraph Set TG-5
— 3 and -f- (plug in, key open)

350*

— 3 and -j- (plug in, key closed)

350*

—3 and L2 (plug in, key closed).

650*

+ and L2 (plug in, key closed) _

180

-j- and L2 (plug out, key closed) _ _

180

22 V — and L2 (plug out, key oper.) . ______

180

22 V — and L2 (plug in, key open)

180

Telegraph Set TG-5-A
— 3 and + (plug in, key open) __ _

700*

— 3 and + (plug in. key closed)

-f-3 and L2 (plug in, key closed). ___

700*
1,000*

4- and L2 (plug in, key closed).

700

-f- and L2 (plug out, key closed) __ _

700

22— and L2 (plug out, key open)

22 — and L2 (plug in, key open). __ __

700
700

Telegraph Set TG-5-B

— 3 and + (plug in, key open)

— 3 and -j- (plug in, key closed)

— 3 and L2 (plug in, key closed). _ __

700*

5,000*

■+- and L2 (plug in, key closed) _

4,500

•j- and L2 (plug out, key closed)

4,500

22 — and L2 (plug out, key open) _

4,500

22 — and L2 (plug in, key open)..

4,500

Resistance may vary + or — 250 ohms.

49. Trouble-shooting Chart

Symptom

Probable trouble

Correction

No transmission; normal

Battery BA-2 dead.
Dirty front key contact.

Replace Battery BA-2.

reception.

Burnish contact.

No reception; normal

Dirty back key contact.

Burnish contact.

transmission.

No reception and no

Open relay winding.

Replace relay.

transmission.

Dirty key contacts.

Burnish contacts. - t

Dirty relay contacts and

Burnish contacts and

dead Battery BA-2.

replace Battery BA-2.

Relay operates but no tone

Dirty relay contacts.

Burnish contacts.

heard in receiver. Head-

Dead Batteries BA-30.

Replace Batteries BA-30.

set plug in jack.

Defective interrupter.

Replace interrupter.

Dirty jack contacts.

Burnish contacts.

Defective headset.

Replace headset.

Relay operates but bell

Dirty relay contacts.

Burnish contacts.

does not ring. Headset
plug removed from jack.

Dead Batteries BA-30.

Replace Batteries BA-30.

Dirty bell contacts.

Burnish contacts.

Defective bell.

Replace bell.

Dirty jack contacts.

Burnish contacts.

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44
Section XIV. REMOVAL AND REPLACEMENT OF PARTS

50. General

When trouble has been localized to a specific unit, it is necessary to gain
access to the defective part to inspect, adjust, or replace it. Parts are
either directly accessible or are reached by removing other parts. Con-
sult the wiring diagram on the equipment when replacing parts to be
certain that the wiring color code is followed accurately.

Note, Those parts of replaced units which can be salvaged should be retained by the
repairman for his own use. If the repairman has no use for them, they should be dis-
posed of through the established channels for salvage. It will be particularly advan-
tageous to retain parts of replaced headsets and interrupters as these units vary in
design when produced by different manufacturers. Possession of such parts may
enable the repairman to make emergency repairs which would be impossible otherwise.

51. Terminal Block

a. Telegraph Set TG-5. (1) Remove the two screws from the back
of the terminal block inside the battery case.

(2) Pull the terminal block away from the mounting. Be careful not
to lose the bakelite spacer from behind the terminal block.

(3) Unsolder the leads from the terminals.

(4) Install a replacement terminal block by reversing the above pro-
cedure. When resoldering the wires on the terminal block be sure to
follow the wiring diagram on the equipment.

b. Telegraph Sets TG-5-A and TG-5-B. (1) Remove the two
screws from the back of the terminal block inside the receiver com-
partment.

(2) Pull the terminal block away from the mounting. Be careful not
to lose the bakelite spacer from behind the terminal block.

(3) Unsolder the leads from the terminals.

(4) Install a replacement terminal block by reversing the above pro-
cedure. Follow the wiring diagram on the equipment for the proper color
code of the wires.

52. Jack

a. Telegraph Set TG-5. (1) Remove the two screws which hold
the jack to the right side of the box.

(2) Pull the jack free of the box.

(3) Unsolder the leads from the terminals.

(4) Install a replacement jack by reversing the above procedure.
Follow the wiring diagram on the equipment for the proper color coding
of wires.

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b. Telegraph Sets TG-5-A and TG-5-B. (1) Remove the two
screws holding the front of the receiver compartment to the side of the
box. Remove the two screws holding the front of the receiver compart-
ment to the battery compartment.

(2) Pull the metal plate and terminal block free of the box.

(3) Remove the two screws that hold the jack to the side of the box.

(4) Unsolder the two leads from the terminals of the rear battery
compartment.

(5) Pull the jack free of the box.

(6) Unsolder the leads from the terminals.

(7) Install a replacement jack by reversing the above procedure. Fol-
low the color code on the wiring diagram mounted on the equipment
when installing a replacement jack.

53. Interrupter

a. Telegraph Set TG-S. (1) Remove the three leads labeled 1, 2,
and 3 from the front of the interrupter.

(2) Remove the two screws that hold the interrupter to the bottcm
of the case.

(3) Pull the interrupter part way out of the box.

(4) Remove the two leads labeled + an d Z from the side of the
interrupter.

( 5 ) Install a replacement interrupter by reversing the above procedure.
(See MWO SIG 11-351-2.) Follow the wiring diagram on the equip-
ment for the proper color coding of wires.

b. Telegraph Sets TG-5-A and TG-5-B. (1) Remove the two leads
labeled 1 and 2 from the front of the interrupter.

(2) Remove the two screws that hold the interrupter to the bottom

of the box.
it

(3) Remove the two leads labeled + and Z from the side of the

interrupter.

(4) Install a replacement interrupter by reversing the above procedure.
Follow the wiring diagram on the equipment for the proper color coding
of wires.

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54. Bell

a. Telegraph Set TG-5. ( 1 ) Remove the three screws which hold the
metal plate over the bell to the side of the box.

(2) Remove the two screws which hold the front of the receiver com-
partment to the battery compartment.

> rij~ifjlf* Original from

Digitized by ^UU^ll UNIVERSITY OF CALIFORNIA

(3) Remove the two screws, one on each side of the bell cover, which
hold the bell to the side of the box.

(4) Pull the bell free of the box. Be careful not to lose the insulated
spacers and washers.

(5) Remove the two leads from the bell terminals.

(6) Install a replacement bell. Follow the wiring diagram on the equip-
, ment for the proper color coding of wires.

b. Telegraph Sets TG-5-A and TG-5-B. (1) Remove the two
screws that hold the bell to the front of the battery compartment.

(2) Pull the bell free of the box. Be careful not to lose the insulated
spacers and washers.

(3) Remove the two leads from the bell terminals.

(4) Install a replacement bell by reversing the above procedure.

55. Capacitor

a. Telegraph Set TG-5. (1) Remove the bell (par. 54), jack (par.
52), and interrupter (par. 53) to permit access to the wiring form.

(2) Remove the two screws from the bracket in the receiver compart-
ment.

(3) Remove the bracket and capacitor from the box.

(4) Cut the lacing on the wiring form far enough to remove the
capacitor leads.

(5) Unsolder the capacitor leads from the terminals.

(6) Install a replacement capacitor by reversing the above procedure.
Follow the wiring diagram on the equipment for the proper color coding

of wires.

(7) Relace the wiring.

b. Telegraph Sets TG-5-A andTG-5-B. (1) Remove the bell. (See
par. 54.)

(2) Remove the two screws that hold the bracket to the bottom of the
box.

(3) Remove the capacitor and terminal plate from the box.

(4) Unsolder the capacitor leads from the terminal plate.

(5) Install a replacement capacitor by reversing the above procedure.
Check the wiring diagram on the equipment for the proper color coding
of wires.

{"'rtj-iril f* Original from

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56. Relay

a. Telegraph Set TG-5. (1) Remove the interrupter. (See par. 53.)

(2) Remove the four screws from the bottom of the box that hold the
relay in place.

(3) Slide the relay to the right and out of the box.

(4) Unsolder the four leads from the end of the relay.
( 5 ) Install a replacement relay by reversing the procedure given above.

Check the wiring diagram on the equipment for proper color coding of
wires.

b. Telegraph Set TG-5-A and TG-5-B. (1) Unsolder the leads
from the relay terminals.

(2) Remove the four screws which hold the relay to the relay mounting
plate. Remove the relay from the plate.

( 3 ) Install a replacement relay by reversing the above procedure. Check
the wiring diagram on the equipment for the proper color coding of wires.

57. Key

a. Remove the three leads from the key by loosening the knurled nuts.

b. Remove the two screws that hold the key to the shelf.

c. Install a replacement key by reversing the above procedure. Check
the wiring diagram on the equipment for proper color coding of wires.

58. Front Cover Catch

a. Telegraph Set TG-5. The catch on Telegraph Set TG-5 is riveted
to the front cover and no attempt should be made to replace it.

b. Telegraph Set TG-5-A. (1) Remove the two screws that hold
the catch to the front cover.

(2) Install a replacement catch.

c. Telegraph Set TG-5-B. (1) Remove the four screws that hold
the catch to the front cover.

(2) Install a replacement catch.

u
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re

Section XV. SPECIAL PROCEDURES

59. Adustment of Relays BK-7 and BK-7-A

(figs. 36 and 37)

a. General. (1) Remove the relay from the box. (See par. 56.)
(2) Turn the relay so that the contact end is up. Turn the top right-hand
contact adjusting screw in as far as it will go. Turn the top left-hand con-
tact adjusting screw out as far as it will go.

^ ni^ii^w hu Cnno \f> Original from

§ Uigmzeo Dy\jUU^lL UNIVERSITY OF CALIFORNIA

b. Adjustment of Armature. (1) Check the contact alignment.

(2) If the armature is not in line with the contacts, adjust it by means
of the pivot screws on the back and front of the relay, until the three con-
tacts are in line.

(3) Tighten the armature pivot screw until there is no sideward move-
ment of the armature, but the armature still moves freely back and forth.

c. Armature Gap Adjustment. (1) Set the GAP adjustment levc
toO.

(2) Loosen the lever setscrew.

(3) Set the lever to 20 and tighten the setscrew.

(4) Move the lever in the direction of until the relay core touches the
armature.

(5) Move the lever back two notches.

(6) Loosen the setscrew and move the lever to 0. Retighten the set-
screw.

d. Spring Tension Adjustment. (1) Loosen the SPRING adjust-
ment lever setscrew.

(2) Turn the spring tension adjustment screw in the back of the relay
until the armature has just enough tension placed upon it to pull it back
to the rear contact.

Note. Turning th« screw in a clockwise direction increases the spring tension on
the armature ; turning the screw in a counterclockwise direction decreases the spring
tension on the armature.

(3) Set the SPRING adjustment lever to and tighten the setscrew.

e. Contact Adjustment. (1) Turn the left contact adjusting screw
in until the break contact pushes the armature up to the relay core.

(2) Turn the top right contact adjusting screw out until the make
contact touches the armature.

(3) Back the break contact up one-half turn of the adjusting screw to
obtain the proper contact separation and armature travel.

/. Replacement of Relay. Replace the relay in the box. (See par. 56.)

60* Adjustment of Relay BK-7-B

(figs. 38 and 39)

a. General. (1) Remove the four screws from the bottom of the relay.

(2) Take the relay off the mounting bracket.

(3) Remove the metal contact cover from the relay.

(4) Remove the three screws from the top of the relay that hold the
bakelite cover in place.

(5) Lift the cover off the relay. Do not pry off the cover.

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§ Digitized Dy ^W^H. UNI VERSITY OF CALIFORNIA

Figure 36. Rear view, Relay BK-7-A*

b. Contact Adjustment. (1) Increase the spring tension, ,by means
of the ADJUST lever, so that the armature is held firmly against the rear
contact.

i BREAK -CONTACT
ADJUSTING SCREW

MAKE-GQNTAGT
ADJUSTING SCREW

ARMATURE

TL63802-S

Figure 37. Contact end, Relay BK-7-A,

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Original from
UNIVERSITY OF CALIFORNIA

(2) Turn the relay so that the contact end is up. Turn the top right-
hand adjusting screw in as far as it will go.

(3*) Turn the top left-hand adjusting screw in until the armature
touches the relay core. Do not increase the pressure against the armature
after it touches the core.

(4) Connect the batteries and headset to the telegraph set.

(5) Back the top right-hand contact adjusting screw out until the frontj
contact touches the armature ; at which time interrupter tone will be hear!
in the receiver.

(6) Back the top left-hand adjusting screw out one-fourth turn. TrSf
interrupter tone in the receiver should stop, and the proper armature trav*el
and* contact separation be obtained.

c. Spring Tension Adjustment. (1) Loosen the ADJUST lever
setscrew, until the lever moves freely without affecting the spring tension
on the armature.

(2) Turn the spring tension adjustment screw in the back of the relay
until the armature has just enough tension placed upon it to pull the
armature back to the rear contact.

Note. Turning the screw in a clockwise direction increases the spring tension.
Turning the screw in a counterclockwise direction decreases the spring tension on
the armature. *

Figure 38. Rear view, Relay BK-7-B.

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Figure 39. Contact end, Relay BK-7-B.

(3) Set the ADJUST lever to 0, and tighten the setscrew, Be careful
when tightening the setscrew not to change the spring tension.

d. Replacement of Relay. (1) Replace the bakelite cover and screws
which hold it in place.

(2) Replace the metal contact cover.
- (3) Place the relay on the relay mounting bracket.

(4) Replace the four screws in the bottom of the relay.

61. Burnishing and Adjusting Contacts of Jack JK— 35

a. Adjustment of Tack Contacts. (1) Remove the jack. (See par.
52.)

(2) Bend the tip contact of the jack so that it rests firmly upon the
phenolic spacer that is secured to the metal base.

(3) Adjust the float contact so that it rests firmly upon the phenolic
spacer on the top of the tip contact. Do not put sharp bends in the contact
springs.

(4) Bend the break contact up until it touches the float contact and
forces the float contact off the phenolic spacer just enough to see light
under it.

(5) Adjust the make contact so that a clearance equal to the thickness
of the screw driver end of Knife TL-29 is attained between the make and
float contacts.

(6) Insert the plug in the jack and check the operation of the jack. The

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Original from
UNIVERSITY OF CALIFORNIA

float should separate from the break contact before contacting the make
contact. The make and break contacts should follow the float before break-
ing contact with it. Remove the plug.

b. Burnishing Contacts. (1) Place the contact burnisher between
the break and float contacts. Be sure the contact burnisher is clean.

(2). Move the contact burnisher back and forth until the contacts are
clean.

(3) Insert the plug in the jack.

(4) Place the contact burnisher between the float and make contacts.

(5) Move the contact burnisher back and forth until the contacts are
clean.

Figure 40. Jack JK-35.

62. Painting and Refinishing

When any painted portion of the box has been scarred or damaged, rust
and corrosion can be prevented by touching up the bared surfaces in the
following manner:

a. Clean the surface of the unit to be refinished with sandpaper ( #00 or
#000). All the finish need not be removed except where the surface film
is broken.

Caution: Do not use steel wool, although it permits rapid removal of
rust. Minute particles of steel wool frequently enter the equipment and
cause harmful internal shorting or grounding of the circuits.

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b. Spray two coats of enamel, olive-drab, low-gloss, air-drying (stock
No. 6G428), or equal, on the case. Air-dry between applications.

63. Unsatisfactory Equipment Report

a. When trouble in equipment used by Army Ground Forces or Army
Service Forces occurs more often than repair personnel feel is normal,
War Department Unsatisfactory Equipment Report, WD AGO Form 468

WAR DEPARTMENT

UNSATISFACTORY EQUIPMENT REPORT

FOR

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TTMkTxg*. &.

MATtRIEL

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MAJOR ITEM

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4£

Maf no. Ola

DEFECTIVE COMPONENT— DESCRIPTION AND CAUSE OF TROUBLE

ANb mOMM GAUM (JJ •4dUkm*J tp*x * rm*»ni,u** buck o//wr) . (/

N OF FAILURE ANb FROSUUBLS GAUM MTootittOMl tpSC* N TtfUtrtd, MM OK* •//***)

c,rt>/9 &fo*/Aj/ ojjf due, & XjtcessrcrtL -»i*/s/uac

BATH OF DOTUU.TWUM

TOTAL TIMC INSTALLED

DAYS

TOTAL PERIOD OF OPERATION BEFORE FAILURE

PUD OKmnnriran or unuwM. ■■IIVICS CONDITIONS' AND ArnuKBMEDIAk ACTION TAKDI y« . , y

OfMofifi undf+AfxjitfMts cfJvGuu**. ->rto/*At*£.. gLb/aeed c<x/kxufa?

TRAINING OR SKILL OF USING I

mutUkmt i Atf to Hftrti. on oars a//wss)

&«r* Zfcy^? cajtaec'/*? cf 4-£° - wftflahLa

ORIGINATING

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FIRST ENI

TO CHIEF

NAME. SMtADE. AND -STATION

AND -STATION /

"OFFICE

Instruction!

L It to tmperattve that the chief of technical service 0""Ttied be advised at the earliest practical moment of any cuu suu o ll o
This form to *^*tr u t* to facilitate cues reports and us ototMo a uniform method of HibmitUnf toe required data.

X This tarn arm be used for reporting manafacturi'»«. design, or operational defectt m materiel, potrotonm fuels, tabrkanto, and preserving materials with a view m

*> Thai form win not be turd ** reporttn* ftiDonw. Isolated material delects or malfunctions of materiel resulting from mlr-wear-and-tear or accidental damage nor lor the

faptocsmraL repair or Um tosoa of par u ana equtpmenL It does not replace currently autboriied operational or performance records.
4 Bcporto of malfunctions and accidents InTolrlnt ammunition wfll continue to be submitted as directed In the manner described In AR 790-10 (change No. J).

a. It will not be practicable or desirable In all cases to nil an blank spaces of the report. However, the report should be at complete as possible In order to expedite neeas>
ear? corrective action. Additional pertinent Information not provided for In Um blank spaces should be submittal

I Whan cases arise where It b neeeasary to communicate with a chtef of service in order to assure safety to personnel, i

■a t horlsed. This form should be used to confirm reports made by more expeditious means.
7. This term wfll be made ont In triplicate by using or service organisation. Two copies wfll bo forwarded direct to the technical serrioai on* copy wtS be I

using this form wfll be determined by the using or service troops.

i supersedes W D.. A. O. O. fotm No. est, I ;
«h may be used until satoting stocks are t

TL53806-S

Figure 41. War Department Unsatisfactory Equipment Report with sample entries.

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(fig. 41), should be filled out and forwarded through channels to the
Office of the Chief Signal Officer, Washington 25, D. C.

b. When trouble in equipment used by Army Air Forces occurs more
often than repair personnel feel is normal, Army Air Forces Fdrm 54
should be filled out and forwarded through channels.

c. If either form is not available, prepare the data according to the
sample form reproduced in figure 41.

E ni^ii^w hu Cnno \f> Original from

§ Uigmzeo Dy\jUU^lL UNIVERSITY OF CALIFORNIA

APPENDIX I
MAINTENANCE PARTS

The following information was compiled on 1 April 1945. The appropriate
sections of the ASF Signal Supply Catalog for Telegraph Set TG-5-(*)
are:

SIG 7-TG-5, Organizational Spare Parts for Telegraph Set TG-5.
SIG 8-TG-5, Higher Echelon Spare Parts for Telegraph Set
TG-5-( ).

For the latest index of available catalog sections, see ASF Signal Supply
Catalog SIG 2.

Ref

Signal Corps

Name

Ref

Signal Corps

Name

symbol

stock No.

symbol

stock No.

Fig. 5

4A2805A/5

BURNISHER

6L3 102-56

NUT, bell
mounting.

Fig. 5

2B832

HEADSET
HS-20

6L3 104^0

NUT, capa-
citor
mounting.

Fig. 5

4Z416

BELL

Fig. 35

3D201

CAPACITOR
CA-210.

6L6256-3.59

SCREW,
catch
mounting.

Fig. 7

4A349A

CASE CS-49-A

6L6256-3.5A

SCREW, bell

Fig. 5

4A2805B/12

CATCH, front
cover.

6L6256-5.7AO

mounting.

SCREW, bell

mounting.

Fig. 5

4A2805B/28

CIRCUIT
DIAGRAM.

Fig. 5

4Z5007 ( )

INTERRUPTER
BZ-7-( )

Fig. 40

2Z5535

JACK JK-35

Fig. 5

3Z3441A

KEY J-41-A

Fig. S

4A20O7B

RELAY BK-7-B

Fig. S

2Z9405.22
4A2005/49

TERMINAL

BLOCK

ASSEMBLY.
BUSHING, bell

mounting.

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Original from
UNIVERSITY OF CALIFORNIA

APPENDIX II
REFERENCES

1 . Army Regulations

AR 380-5, Safeguarding Military Information.

2. Parts Lists

SIG 1, Introduction to ASF Signal Supply Catalog.

SIG 2, Complete Index to ASF Signal Supply Catalog.

SIG 3, List of Items for Troop Issue.

SIG 4-1, Allowances of Expendable Supplies.

SIG 4-2, Allowances of Expendable Supplies for Schools,

Training Centers, and Boards.
SIG 5, Stock List of all Items.

SIG 6, Sets and P & I Control List. j

SIG 7-TG-5, Organizational Spare Parts for Telegraph Set TG-5. j
SIG8-TG-5, Higher Echelon Spare Parts for Telegraph Set !
" TG-( ). |

SIG 10, Signal Supply Catalog Fixed Plant Maintenance

Lists. , ;

SB 11-6, Dry Battery Supply Data.

3. Technical Manuals on Test Equipment

TM 11-2017, Test Set TS-26/TSM.
TM 11-2613, Voltohmmeter 1-166.

D1 '

4. Painting, Preserving, and Lubrication

TB SIG 123, Preventive Maintenance Practices for Ground Signal
Equipment.

5. Shipping Instructions

U.S. Army spec No. 100-14A, Army- Navy General Specifications
for Packaging and Packing for Oversea shipment.

6. Decontamination

TM 3-220, Decontamination.

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§ by \juugic UNIVERSITY OF CALIFORNIA

7. Demolition

FM 5-25, Explosives and Demolitions.

8. Camouflage

FM 5-20, Camouflage, Basic Principles.

9. Other Technical Publications

FM 21-6, List of Publications for Training.

FM 21-7, List of War Department Films, Film Strips, and Recog-
nition Film Slides.

FM 21-8, Military Training Aids.

FM 21-40, Defense Against Chemical Attack.

FM 24-5, Signal Communication.

TB SIG 13, Moistureproofing and Fungiproofing Signal Corps
Equipment.

TB SIG 29, Impedance Unbalance Tests for Coils C-161 and C-
228.

TB SIG 37, Grounding Requirements and Procedure Applicable to
Wire Communication and Associated Electrical Apparatus.

TB SIG 66, Winter Maintenance of Signal Equipment.

TB SIG 69, Lubrication of Ground Signal Equipment.

TB SIG 72, Tropical Maintenance of Ground Signal Equipment.

TB SIG 75, Desert Maintenance of Ground Signal Equipment.

TB SIG 96, Repair Instructions for Field and Long Range Tactical
Wire.

TB SIG 101, Longe-range Tactical Wire W-143.

TB SIG 121, Instructions for Tying and Use of Weave Tie for
Field Wires and Cables.

TB SIG 123, Preventive Maintenance Practice for Ground Signal
Equipment.

TB SIG 150, Wire Dispenser MX-301/G.

TB 11-430-1, Maintenance of Batteries in Nontemperate Areas.

TM 1-455, Electrical Fundamentals.

TM 11-430, Batteries for Signal Communication Except Those Per-
taining to Aircraft.

TM 1 1-432, Code Practice Equipment.

TM 1 1-450, Training of Signal Communication Personnel.

TM 11-456, Wire Telegraphy.

TM 1 1-459, Instructions for Learning International Morse Code
Characters.

TM 1 1-462, Signal Corps Reference Data.

TM 11-498, Fundamentals of Telephony and Manual Telegraphy.

TM 37-250, Basic Maintenance Manual.

{"'f^j^riL^ Original from

Digitized by Vj-UU^IL UNIVERSITY OF CALIFORNIA

10. Forms

WD AGO Form 468, Unsatisfactory Equipment Report.
AAF Form 54, Unsatisfactory Report.

1 1 . Abbreviations

AAF Army Air Forces

AGO Adjutant General's Office

ASF Army Service Forces

d-c direct-current

fig figure

mf microfarad

No number

par paragraph

rcvr receiver

spec specification

subpar subparagraph

term terminal

v volt (s)

WD War Department

xmtr transmitter

$-U. S. Government Printing Office: 1945 — 628023

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